From 1a962286b8c4829b1378b8442f2be07adf59c6db Mon Sep 17 00:00:00 2001
From: zhenzi <tianzhenzi@inke.cn>
Date: Sat, 15 May 2021 12:02:59 +0800
Subject: [PATCH] =?UTF-8?q?Update=200509.=E6=96=90=E6=B3=A2=E9=82=A3?=
 =?UTF-8?q?=E5=A5=91=E6=95=B0.md?=
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---
 problems/0509.斐波那契数.md | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/problems/0509.斐波那契数.md b/problems/0509.斐波那契数.md
index 8537ed8b..8be11312 100644
--- a/problems/0509.斐波那契数.md
+++ b/problems/0509.斐波那契数.md
@@ -171,7 +171,20 @@ public:
 
 
 Java：
-
+```Java
+class Solution {
+    public int fib(int n) {
+        if (n < 2) return n;
+        int a = 0, b = 1, c = 0;
+        for (int i = 1; i < n; i++) {
+            c = a + b;
+            a = b;
+            b = c;
+        }
+        return c;
+    }
+}
+```
 
 Python：